Law Abiding Citizen is a 2009 US thriller by F Gary Gray
The US Unrated Version or Director’s Cut was passed 18 for the 2010 Technicolor Blu-ray
The Theatrical Version was passed 18 without cuts for the 2009 cinema release and 2010 Technicolor DVD
The additional material for the Director’s Cutis is mostly plot and dialogue, but the violent scenes, including the rape and torture, have been extended too.
See pictorial version details from movie-censorship.com
The BBFC explained the 18 rating:
Law Abiding Citizen is a thriller about a man who feels let down by the US justice system after his wife and daughter are murdered. The film has been classified at 18 for strong bloody violence, torture and sexual violence.
The film contains several scenes of strong violence, with a bloody and protracted stabbing in one instance. BBFC Guidelines at 15 state that violence may not dwell on the infliction of pain and injury. At least one of the scenes was judged to go beyond the scope of the Guidelines at 15. Other scenes imply strong violence, including torture, but in most instances the strong detail is not seen on screen. The film includes one scene of sexual violence, with the attack implied rather than portrayed.
Law Abiding Citizen contains a vigilante theme, with a man taking the concept of justice into his own hands and using violence against those who he judges to have failed him. This theme was also considered suitable only at 18. The BBFC Guidelines require caution with themes that appear to endorse illegal behaviour, such as violent revenge. In this instance there is some ambiguity as to how the vigilante is presented, with some dialogue references to the lack of wisdom of his choices, but this is counterbalanced with him being presented as a sympathetic character.
The film also includes frequent use of strong language.